6.8 Example from Nairobi, Kenya

Sanergy uses black soldier fly larvae to treat and upcycle faecal sludge and other organic waste in Nairobi. Faecal sludge is collected from Fresh Life Toilets, container-based systems that separate urine and faeces. As of December 2019, Sanergy had installed 3,247 Fresh Life Toilets in 11 informal settlements, serving over 80,000 urban residents. The containers are double-sealed and transported to the treatment plant by handcarts, vehicles, and trucks.

The BSF larvae feed on food and agricultural waste mixed in with the faecal sludge. The larvae consume the organic matter and grow from a few millimetres to around 2.5 cm in 14 to 16 days while reducing the wet weight of the waste by up to 80%. The BSF larvae are harvested before the prepupal stage using a mechanical agitator. The larvae are marketed as animal feed, as they have high protein (35%) and fat (30%) content. The frass residue is the excrement from the larvae, is mixed with organic waste and composted to produce organic fertiliser.

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